<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title>Pulsing Heart</title>
        <style media="screen">
            body{
                text-align: center;
            }
            @keyframes pulsing-heart {
                0%{transform: none;}
                50%{transform: scale(1.4);}
                100%{transform: none;}
            }
            .heart{
                font-size: 10rem;
                color: #FF0000;
            }
            .heart:hover{
                animation: pulsing-heart .5s infinite;
                transform-origin: center;
            }
        </style>
    </head>
    <body>
        <div>
            <div class="heart">&hearts;</div>
        </div>
    </body>
    </html>